Access to the knee and/or shoulder joints during arthroscopic surgery is typically made through two portals, often referred to as the operative portal and the visualization portal. An arthroscope is inserted through the visualization portal, while a surgical instrument is inserted through the operative portal. If desired, the role of the visualization portal can be interchanged with the role of the operative portal to provide better viewing of, and/or better access to, internal capsular structures.
The hip is complex and difficult to access using arthroscopic techniques. FIGS. 1, 2A, 2B, 2C and 2D illustrate the basic anatomy of the hip. For the sake of simplification, FIGS. 1, 2A, 2B, 2C and 2D do not show the surrounding synovial membrane, the femoral ligament complex, the adductor muscle structure, varying layers of fat, and other tissue, all of which compound the difficulty in accessing the joint capsule. There are also many delicate structures surrounding the hip joint that are not shown in FIGS. 1, 2A, 2B, 2C and 2D, e.g., the anterior femoral neurovascular bundle, the lateral femoral cutaneous nerve, the lateral femoral circumflex artery and the sciatic nerve, among others. Damage to these structures can be permanent and irreparable, so care must be taken to avoid harming these structures during surgery.
Typically, access to the hip joint for minimally invasive arthroscopic surgery is achieved through two access cannulas which line the aforementioned operative portal and visualization portal. The two access cannulas are typically positioned in the so-called posterolateral and anterolateral positions, which are located 1-2 cm above (superior) and 1-2 cm on each side of the landmark greater trocanter (see FIG. 3). Typically, the arthroscope is disposed in the posterolateral position and the surgical instrument (e.g., forceps, dissector, scissors, scalpel, punch, probe, powered shaver, manual graspers, electrocautery wand, etc.) is disposed in the anterolateral position. However, as noted above, it is common to interchange this positioning in order to improve visualization and/or access to the target site.
Despite the ability to interchange the positioning of the arthroscope and surgical instrument, areas of the distended surfaces of the hip joint are generally not able to be fully visualized. FIG. 3 shows one such “No See” zone. The regions of the hip joint which are not accessible by straight and rigid surgical instruments is even larger due to the anatomy of the hip joint and the fixed geometry of the surgical instruments. For example, if the target site is in a region that is located on the far side of the femoral head, a third portal must often be established in the so-called anterior position. However, this anterior portal considerably increases the risk associated with the procedure, due to the proximity of the third portal to the lateral femoral cutaneous nerve, the lateral femoral circumflex artery and the femoral neurovascular bundle. Unfortunately, access via the opposite, posterior side of the joint, i.e., via the gluteal region, is generally not a viable option, nor is access via a medial approach from the groin.
Roughly half of the distended hip joint is inaccessible via the normal, accepted portal placement positions (i.e., the aforementioned posterolateral and anterolateral positions). While visualization can be improved somewhat by physically “prying” the access cannulas into a contrived position, and/or by performing excessive capsulectomies, access remains a significant hurdle to the performance of arthroscopic procedures on the hip.
The preferred solution would be to provide steerable surgical instruments that can enter the capsule of the hip joint in a straight configuration through any of the access portals commonly used (e.g., the aforementioned posterolateral and anterolateral portals), and then be steered into a “No See” zone, e.g., as depicted in FIG. 4. Preferably, this steerable surgical instrument would have a robust straight section 120 and a steerable section 122 that is set to a straight configuration during insertion into the capsule and is then steered into the operable position through the manipulation of controls housed in an instrument handle positioned outside the capsule and connected to the proximal end of straight section 122.